AS1 (Applicability Statement 1) is a specification for Electronic Data Interchange (EDI) communications between businesses using e-mail protocols. The specification has been largely superseded by Applicability Statement 2 (AS2). Both specifications were created by EDI over the Internet (EDIINT), a working group of the Internet Engineering Task Force (IETF) for developing secure and reliable business communications standards.
The AS1 standard provides S/MIME (Secure Multi-Purpose Internet Mail Extensions) and uses Simple Mail Transfer Protocol (SMTP) to transmit data using e-mail. Security, authentication, message integrity, and privacy are assured by the use of encryption and digital signatures. Another important feature, nonrepudiation, makes it impossible for the intended recipient of a message to deny having received it.
An Internet connection capable of sending and receiving e-mail, an EDI transfer engine, and digital certificates are required for data exchange using AS1. Almost any type of data can be transmitted.